DESY

DESY's function is to conduct fundamental research for solely civil and peaceful purposes. It specialises in particle accelerator development, construction and operation, particle physics, astroparticle physics and photon science research to explore the fundamental relationships between the structure, dynamics and function of matter. In cooperation with its partner organisations, its photon science research spans surface physics, material science, chemistry, molecular biology, geophysics and medicine through the use of synchrotron radiation and free-electron lasers.[1][2]

In addition to operating its own large accelerator facilities, DESY participates in many major international research projects, for example the European X-Ray Free-Electron Laser in Germany, the Large Hadron Collider in Switzerland, the Belle II experiment in Japan, the IceCube Neutrino Observatory at the South Pole and the worldwide Cherenkov Telescope Array.[3]

Main entrance of the DESY campus in Hamburg

DESY operates in two locations. The primary location is in the Bahrenfeld quarter of Hamburg. In 1992, DESY expanded to a second site in Zeuthen near Berlin.

DESY employs about 2,700 staff members from more than 60 nations. 2,430 people work at the Hamburg site, about 270 at the Zeuthen site. These numbers include more than 130 trainees in various industrial-technical professions and about 500 PhD students and postdocs supervised by DESY. In addition, there are numerous master students from various universities.[5]

The research centre is a foundation under civil law financed by public funds. In 2020, DESY had an annual budget of about 232 million euros (according to the German federal budget plan, excluding expenditure for investments and special financing expenses). In addition, it had a third-party funding income of about 18 million euros. 90% of the annual budget is provided by the German Federal Ministry of Education and Research (German: Bundesministerium für Bildung und Forschung)[6] and 10% respectively by the Free and Hanseatic City of Hamburg[7] and the German federal state of Brandenburg.[8]

View inside the PETRA III "Max von Laue" hall on the DESY campus in Hamburg

FLASH2 experimental hall on the DESY campus in Hamburg

LINAC II and DESY II are electron pre-accelerators for the storage ring PETRA III, which, together with the free-electron laser FLASH, serves as a light source for photon science. Also shown is the European XFEL X-ray laser, which runs from the DESY campus to the town of Schenefeld in Schleswig-Holstein.

DESY's accelerators were not all built at once, but were rather added one by one to meet the growing demand of the scientists for higher and higher energies to gain more insight into particle structures. In the course of the construction of new accelerators, the older ones were converted to pre-accelerators or to sources for synchrotron radiation for laboratories with new research tasks.

Research at DESY is organised into four divisions: Accelerators, Photon Science, Particle Physics and Astroparticle Physics.

The superconducting resonators used in the linear accelerators of the free-electron laser FLASH and the European XFEL X-ray laser are processed and assembled in a cleanroom.

The Accelerator division develops fundamental technologies for the accelerator facilities that DESY and its partners use in their scientific mission. In addition to the operation and further development of existing facilities (PETRA IV and FLASH2020+ projects, expansion of the European XFEL), essential activities include research into new accelerator concepts, in particular plasma wakefield acceleration, and the improvement of superconducting radio frequency accelerator technology.[17][18]

Experiments to investigate the SARS-CoV-2 virus at the PETRA III synchrotron radiation source at DESY

In the Photon Science division, photons are being used to study the structure, dynamics and function of matter. To this end, the division develops, builds and operates beamlines and experiments at the DESY light sources PETRA III and FLASH. Every year, more than 3,000 researchers – most of them from universities, but also from non-university research institutions and industry – from over 40 countries conduct experiments at the light sources and in the laboratories at DESY.[19] The research spectrum ranges from basic research to applied research and industrial collaborations in physics, chemistry, biology, medicine, life sciences, earth sciences, materials research as well as the study of cultural heritage.[20]

In the Detector Assembly Facility (DAF) at DESY, new, more radiation-resistant and precise silicon tracking detectors are produced for the ATLAS and CMS experiments at the LHC accelerator at CERN (here for CMS).

The Particle Physics division is involved in the large-scale experiments at the Large Hadron Collider (LHC) at CERN near Geneva. As part of the international collaborations that run the ATLAS and CMS experiments, DESY contributes to many developments at the LHC, from hardware design and data analysis to preparations for the planned upgrades. DESY also participates in the Belle II experiment at the electron–positron collider SuperKEKB at the research centre KEK in Tsukuba, Japan, as well as in developments for possible future electron–positron linear colliders. It is also active in theoretical particle physics.[21][22]

DESY produces a large part of the digital optical modules for the neutrino observatory IceCube at the South Pole.

The Astroparticle Physics division investigates high-energy processes in the universe. Detectors and telescopes are used to analyse neutrinos and gamma rays from space, which can provide information about cosmic phenomena: black holes, exploding stars and radiation bursts of extreme intensity. To this end, DESY is involved in the gamma telescopes MAGIC, H.E.S.S. and VERITAS as well as the Fermi Gamma-ray Space Telescope, and it contributes to the planned Cherenkov Telescope Array (CTA). It is the second largest partner in the IceCube observatory at the South Pole.[23][24]

German 1984 postal stamp – 25th anniversary of the foundation of DESY

DESY was founded on 18 December 1959 in Hamburg.[25] According to its statutes, DESY's mission is "the promotion of basic scientific research [...] in particular through the development, construction and operation of accelerators and their scientific use, in photon science and in the fields of particle and astroparticle physics, as well as through research and development work related thereto".[26]

The ARGUS detector at the former electron–positron storage ring DORIS at DESY

In 1979, the particle physics experiments at the electron–positron storage ring PETRA at DESY discovered the gluon, the messenger particle of the strong force.

From 1959 to 2007, the DESY accelerators were primarily used for particle physics, initially with the eponymous DESY electron synchrotron (1964–present), followed by DORIS (Double Ring Storage Facility, 1974–1992), PETRA (Positron–Electron Tandem Ring Facility, 1978–present) and HERA (Hadron–Electron Ring Accelerator, 1992–2007). In 1987, the ARGUS experiment at DORIS was the first to observe a large mixing of B mesons and thus a process in which matter and antimatter behave differently.[25][27] The most important discovery of the experiments TASSO, JADE, MARK-J and PLUTO at PETRA was the detection of the gluon, the messenger particle of the strong force, in 1979.[25] From 1990, PETRA served as a pre-accelerator for the even larger storage ring HERA with its four experiments H1, ZEUS, HERMES and HERA-B. HERA was the only storage ring facility in the world in which protons collided with electrons or positrons. In these collisions, the point-like electron acted like a probe, scanning the inner structure of the proton and making it visible with high resolution. HERA's precise insights into the interior of the proton formed the basis for numerous other particle physics experiments, especially at the Large Hadron Collider (LHC) at the research centre CERN and for numerous developments in theoretical particle physics.[25][28]

"Max von Laue" experimental hall at the synchrotron radiation source PETRA III on the DESY campus in Hamburg

In parallel, as early as the 1960s, research groups from DESY, various universities and the Max Planck Society developed the technology for using the synchrotron radiation produced by the accelerators.[29] To meet the rapidly growing national and European demand, DESY founded its own large laboratory: the Hamburg Synchrotron Radiation Laboratory HASYLAB, which opened in 1980.[30] It provided measuring stations at DORIS, and it was here that the Israeli biochemist Ada Yonath (Nobel Prize in Chemistry 2009) conducted experiments from 1986 to 2004 that led to her deciphering the ribosome.[25][31] From 1995, both synchrotron radiation and particle physics experiments were conducted at PETRA. In 2009, the PETRA facility was upgraded for exclusive use as a synchrotron radiation source for hard X-rays (PETRA III).[25] Today, PETRA III serves over 40 experimental stations, and there are plans to expand it into the PETRA IV 3D X-ray microscope.[32][33] With the shutdown of DORIS in early 2013, the name HASYLAB was abandoned, and the use of DESY's light sources has since been carried out in its Photon Science division.

In the free-electron laser FLASH at DESY, electrons generate laser light in the soft X-ray range as they pass through special magnetic arrangements known as undulators (yellow).

In the early 1990s, DESY began to develop a new technology: radio frequency accelerator technology based on superconducting cavities made of niobium, which are cooled to approximately 2 K (−271 °C) with liquid helium. The first accelerator on this basis was a test facility for superconducting linear accelerators at DESY to test the principle of self-amplified spontaneous emission (SASE) of X-ray laser light.[34] The SASE theory was developed and refined at DESY and at institutes in Russia, Italy and the USA from 1980 onwards.[35] In 2000 to 2001, the test facility at DESY was the first free-electron laser in the world to produce light flashes in the vacuum ultraviolet and soft X-ray range.[36] Today, the FLASH facility produces ultrashort light pulses in the soft X-ray range for seven experimental stations.[37] Since 2020, it has been expanded to further optimise the properties of the radiation (FLASH2020+ project).[38]

From 2009 to 2016, an international consortium led by DESY developed the European X-ray free-electron laser European XFEL. The international research facility, which involves 12 European shareholder countries, is operated by the non-profit company European XFEL GmbH. The core of the facility is a 1.7 km superconducting linear accelerator. With an electron energy of 17.5 GeV, it is the most powerful superconducting linear accelerator in the world to date. DESY operates the accelerator on behalf of European XFEL GmbH.[39][40]

Since 2010, DESY has been developing plasma-based accelerator technology (both laser- and electron-beam-driven) as a possible alternative to conventional accelerator technologies, with the aim of enabling compact accelerators for photon science, particle physics as well as medical and industrial applications.[41]

DESY is headed by a Directorate consisting of the directors of the four divisions (Accelerators, Photon Science, Particle Physics and Astroparticle Physics) and the administration as well as the delegate of the Directorate for innovation. Chairpersons of the Directorate so far have been:[25]

• 1959 to 1970: Willibald Jentschke, Founding Director
• 1971 to 1972: Wolfgang Paul
• 1973 to 1980: Herwig Schopper
• 1981 to 1993: Volker Soergel
• 1993 to 1999: Bjørn H. Wiik
• 1999 to early 2009: Albrecht Wagner
• since 2 March 2009: Helmut Dosch

Inside the Centre for Free-Electron Laser Science (CFEL) in Hamburg

The DESY campus in Hamburg is the location of several national and international centres in which DESY participates. These are:[42]

• Centre for Free-Electron Laser Science (CFEL): Investigation of ultrafast phenomena with free-electron lasers and optical lasers, studies of light–matter interaction under extreme conditions
• Centre for Structural Systems Biology (CSSB): Structural systems biology to study infection processes at the molecular level of viruses, bacteria and parasites
• Centre for X-ray and Nano Science (CXNS): Investigation of condensed matter with X-ray and complementary methods, high-resolution X-ray imaging, analysis of material processes

The Start-up Labs Bahrenfeld, an innovation centre of DESY, the University of Hamburg and the Free and Hanseatic City of Hamburg were opened in September 2021.

DESY aims to promote start-ups and bring know-how from fundamental research into application. It offers commercial companies support for industrial issues, e.g. through special industry access to photon sources and laboratories, develops ideas, applications and products based on fundamental research, and supports its employees in founding start-ups based on DESY technologies in the Hamburg and Brandenburg regions. DESY offers start-ups access to offices, laboratories and workshops in the DESY Innovation Village and the Start-up Labs Bahrenfeld, established together with the University of Hamburg and the Free and Hanseatic City of Hamburg.

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